1. Field of Invention
The present invention relates to a method for adjusting the transmission speed, and more particularly to a method for adjusting the transmission speed of the electronic aid, which is capable of self-correcting the transmission speed of the electronic aid.
2. Description of Related Arts
With the development of the electric industry, more and more electronic aids have been widely used, such as the USB (Universal Serial Bus) 2.0 high-speed electronic aids (including U disks, MP3s, card readers and so on). These electronic aids are connected with computers by USB interfaces to acquire the data from the computers, or transfer the data to the computers for achieving their functions. However, the quality of the connecting lines of some existing USB 2.0 electronic aids is getting worse and worse, so the performances of these electronic aids are decreased while working. Under some bad conditions, some devices may not work normally.
Referring to FIG. 1, a flow chart of a computer identification electronic aid of the prior art is shown. According to the USB 2.0 protocol, it is necessary for the USB 2.0 electronic aid to firstly make a rate negotiation with the computer before the USB 2.0 electronic aid works normally. If the electronic aid supports the high-speed operation mode, the electronic aid will firstly make the rate negotiation of the high-speed transmission speed with the computer. After the success of the negotiation, the computer begins to send the high-speed data packet to the electronic aid for identifying and initially configuring the electronic aid, such that the electronic aid begins to work normally. If the high-speed rate negotiation between the electronic aid and the computer is unsuccessful, the electronic aid will automatically switch to the full-speed operation mode, such that the data are transferred between the electronic aid and the computer. However, if the high-speed rate negotiation between the electronic aid and the computer is successful, but the data still can not be transferred normally between the electronic aid and the computer, the electronic aid will not work normally. According to the USB 2.0 protocol, under the condition that the electronic aid can not work normally, the computer has three opportunities to retry. For every opportunity, the computer firstly makes the rate negotiation with the electronic aid, if it works, the data packet will be sent to the electronic aid. If the data still can not be transferred normally between the electronic aid and the computer after three retrials, the electronic aid will not be identified. Therefore, the electronic aid can not work normally.